Social Network can refer to as a social structure made up of a set of social actors (such as individuals or organizations), sets of dyadic ties, and other social interactions between actors. Computer networks combined with social networking software produces a new medium for social interaction, a virtual community or profile site, a website that brings people together to talk, share ideas and interests, or make new friends.

In the present book, fifteen typical literatures about Social Network published on international authoritative journals were selected to introduce the worldwide newest progress, which contains reviews or original researches on health, medical science, mental disease, ect. We hope this book can demonstrate advances in Social Network as well as give references to the researchers, students and other related people.